The present invention relates to a bonded nonwoven material, and method and apparatus for forming the same. In particular, the present invention relates to a nonwoven web (either elastic or nonelastic), and a nonwoven laminate (e.g., a nonwoven fibrous elastic laminate comprising at least one nonwoven elastic web together with at least one further nonwoven web), with the material (either a single web or laminate) being bonded to form the bonded nonwoven material.
It has been desired to provide bonded nonwoven materials (e.g., nonwoven webs, either elastic or nonelastic, of a single web or of a laminate) having high overall bulk, hand and drape. It has been particularly desired to provide such nonwoven material having high overall bulk, from an initial material with high bulk but not sufficiently self-supporting, wherein the final product (which is sufficiently self-supporting) has been bonded while avoiding any substantial decrease in overall bulk, the final product retaining good hand and draping properties after bonding.
It has also been desired to provide nonwoven elastic laminates that are both stretchable and resilient, and which retain good hand and draping properties after bonding.
U.S. Pat. No. 4,016,317 to Kalwaites discloses nonwoven fabrics having patterns of areas of low fiber density or holes and patterns of fiber bundles of parallelized consolidated fiber segments, the predetermined pattern of areas being partially or entirely defined by yarn-like fiber bundles, the junctures in the fabric (that is, the areas where the fiber bundles intersect one another) possibly comprising areas of highly entangled fiber segments. The described fabric has one surface which is smooth and substantially free of fiber ends, while the opposite surface contains a plurality of fiber ends held together by a binder to form tufts of bonded fiber ends on the surface. This patent discloses that the fabric is formed by placing a fibrous web comprising staple length fibers on a foraminous support wire, the foraminous support having from about 200 to about 8100 openings per square inch to provide from about 20 to 70% open area in the support so that the staple length fibers will span at least two of the openings, with fiber rearranging forces being directed against the fibrous web to move fiber segments into closer proximity to one another and increased parallelism to form fiber bundles defining areas of low fiber density therebetween, individual fiber ends being forced down through the openings in the foraminous support member. This patent discloses specific apparatus including a rotatable apertured drum. Inside the drum is a stationary manifold to which a fluid is applied; on one side of the manifold is a series of nozzles for directing the fluid toward the drum periphery. A backing belt extends about a large portion of the periphery of the drum, and, together with the apertured drum, provides a rearranging zone between them through which a fibrous material moves to be rearranged, under the influence of applied fluid forces, into a nonwoven fabric having the previously discussed pattern.
Kalwaites describes use of staple length fibers which span at least two of the openings in the support wire; the present invention is not so limited, and, as discussed further herein, is applicable to fibers having lengths less than staple fibers (that is, is applicable to pulp fibers, even those having lengths less than 0.25 inch). In Kalwaites, fiber rearrangement occurs so as to provide areas of low fiber density; such areas of low fiber density are weak points in the final structure. In the present invention, on the other hand, the holes and low density areas are limited; and when meltblown fibers are used in the present invention, areas of low fiber density are avoided.
U.S. Pat. No. 3,485,706 to Evans discloses a textile-like nonwoven fabric and a process and apparatus for its production, wherein the fabric has fibers randomly entangled with each other in a repeating pattern of localized entangled regions interconnected by fibers extending between adjacent entangled regions. The process disclosed in this patent involves supporting a layer of fibrous material on an apertured patterning member for treatment, jetting liquid supplied at pressures of at least 200 pounds per square inch (psi) gauge to form streams having over 23,000 energy flux in foot-pounds/inch.sup.2.second at the treatment distance, and traversing the supporting layer of fibrous material with the streams to entangle fibers in a pattern determined by the supporting member, using a sufficient amount of treatment to produce uniformly patterned fabric. The initial material is disclosed to consist of any web, mat, batt or the like of loose fibers disposed in random relationship with one another or in any degree of alignment.
U.S. Pat. No. 4,209,563 to Sisson discloses a method of forming an elastic cloth structure, and the cloth structure formed, including simultaneously melt spinning a stream of filaments of fiber-forming synthetic organic polymer from an extruder through a die or a spinnerette, the filaments then being mechanically reduced to textile denier by being drawn, e.g., by a draw roll, the drawn filaments then being forwarded by forwarding means to random or directed formation onto a moving porous forming surface, with the filaments being bonded following laydown or collection. In accordance with one aspect disclosed in this patent, a cloth structure is formed comprised of at least two types of preferably continuous filaments, at least one of which is relatively elastomeric and at least one of which is elongatable but relatively nonelastic; at least one of these types of filaments is dispersed to provide frequent random fiber crossings at least some of which are bonded, either directly or indirectly and preferably autogenously, to form a coherent cloth. Subsequent to forming the coherent (bonded) cloth, the bonded cloth, e.g., is stretched, preferably substantially and uniformly in at least one direction, followed by substantially complete cloth relaxation to develop a low modulus of elasticity therein in at least such one direction. This patent goes on to describe that the relatively elastomeric filaments and elongatable but relatively nonelastic filaments can be laid as superposed layers or as a mixed layer to provide numerous well dispersed fiber crossings weld bonded by the application of heat and pressure to at least some of the fiber crossings to provide a coherent bonded nonwoven cloth.
U.S. Pat. No. 4,296,163 to Emi et al discloses a fibrous composite having elasticity, comprised of a coalesced assembly of (A) a sheet-like mesh structure composed of fibers of a synthetic elastomeric polymer, the individual fibers of which are interconnected at random in irregular relationship to form a number of meshes of different sizes and shapes, with the mesh structure having a recovery ratio after 10% stretch of at least 70% in two arbitrarily selected, mutually perpendicular directions on the plane of the mesh structure, and (B) a mat-, web- or sheet-like fiber structure composed of short or long fibers, with the fiber structure having a recovery ratio after 10% stretch of less than 50% in at least one arbitrarily selected direction. It is stated that the formed elastic composite is suitable for various apparel-based materials and industrial materials such as filter cloths, absorbents, and heat insulating materials.
U.S. Pat. No. 4,514,455 to Hwang discloses a composite nonwoven fabric which comprises a batt of crimped polyester staple fibers and a bonded sheet of substantially continuous polyester filaments. The batt and sheet are in surface contact with each other and are attached to each other by a series of parallel seams having a spacing of at least 1.7 cm between successive seams. In one embodiment, the seams are jet tracks which are a result of hydraulic stitching. In the fabric produced in Hwang, the bonds are interconnected in the continuous jet tracks, while in the present invention the spots of bonding area are not connected with each other.
U.S. Reissue Pat. No. 31,601 to Ikeda et al discloses a fabric, useful as a substratum for artificial leather, which comprises a woven or knitted fabric constituent and a nonwoven fabric constituent. The nonwoven fabric constituent consists of numerous extremely fine individual fibers which have an average diameter of 0.1 to 6.0 microns and which are randomly distributed and entangled with each other to form a body of nonwoven fabric. The nonwoven fabric constituent and the woven or knitted fabric constituent are superimposed and bonded together, to form a body of composite fabric, in such a manner that a portion of the extremely fine individual fibers and the nonwoven fabric constituent penetrate into the inside of the woven or knitted fabric constituent and are entangled with a portion of the fibers therein. The composite fabric is disclosed as being produced by superimposing the two fabric constituents on each other and jetting numerous fluid streams ejected under a pressure of from 15 to 100 kg/cm.sup.2 toward the surface of the fibrous web constituent. This patent discloses that the extremely fine fibers can be produced by using any of the conventional fiber-producing methods, preferably a meltblowing method.
U.S. Pat. No. 4,446,189 to Romanek discloses a nonwoven textile fabric laminate which includes at least one layer of nonwoven textile fabric which is elongatable, and which is secured by needle punching to an elastic layer so that the nonwoven layer of textile fabric will be permanently stretched when the elastic layer is drafted within its elastic limits. After such drafting, when the elastic layer is allowed to relax and return to substantially its condition prior to being drafted, the nonwoven fabric layer is stated to exhibit increased bulk as a result of its concurrent relaxation. It is also stated that the nonwoven textile fabric laminate may be utilized to form wearing apparel which has enhanced freedom of movement.
U.S. Pat. No. 4,657,802 to Morman discloses a process for producing a composite nonwoven elastic web which is composed of a nonwoven elastic web that is joined to a fibrous nonwoven gathered web, and the composite web formed. The composite elastic web, according to U.S. Pat. No. 4,657,802, is formed by joining the fibrous nonwoven gatherable web to the nonwoven elastic web (e.g., forming the gatherable web on the elastic web) while the nonwoven elastic web is maintained at an elongated (stretched), biased length; because the fibrous nonwoven gatherable web is formed onto the surface of the nonwoven elastic web while the elastic web is being maintained at its stretched, biased length, the fibrous nonwoven gatherable web is in an ungathered but gatherable condition. In one embodiment described in this patent, joining of the gatherable and elastic webs is achieved by heat-bonding to fuse the two webs to each other; in another embodiment, joining of the fibrous nonwoven gatherable web to the stretched nonwoven elastic web is achieved solely by the entanglement of the fibers of the fibrous nonwoven gatherable web with the nonwoven elastic web during formation of the fibrous gatherable web on the surface of the elastic web. In connection with this latter embodiment, the patent discloses that if the nonwoven elastic web is a fibrous nonwoven elastic web formed by, e.g., meltblowing, entanglement of the fibers of the fibrous nonwoven gatherable web with the fibrous nonwoven elastic web is achieved by entanglement of the fibers of the fibrous gatherable web with the fibers of the fibrous elastic web. In a still further embodiment described in this patent, the nonwoven elastic web is made out of a tacky elastic material, whereby the fibrous nonwoven gatherable material is adhesively joined to the surface of the tacky elastic web. This patent goes on to disclose that, in any of these embodiments, after joining of the two webs to each other to form a composite elastic web, the biasing force is removed from the composite nonwoven elastic web and the composite elastic web is allowed to relax to its normal relaxed, unbiased length, resulting in the gatherable web being carried with the contracting nonwoven elastic web and thus being gathered.
Notwithstanding the teachings of the above-discussed references, it is desired to provide bonded nonwoven material having high overall bulk, and, in particular, wherein the overall bulk of the material subjected to bonding (to form the bonded nonwoven material) is not substantially decreased by the bonding, while providing a bonded nonwoven material having good hand and drape. It is desired to provide a bonded nonwoven material, of either a single web or a laminate, of an elastic and/or a nonelastic material, having high overall bulk and good hand and drape. It is desired to provide such bonded nonwoven material without use of conventional bonding techniques such as fusion or chemical bonding, mechanical needling, etc.
Moreover, notwithstanding the teachings of the above-discussed references, there is still a desire to provide bonded elastic nonwoven materials that retain high overall bulk after bonding and have good stretch and recovery properties, without decreased hand and draping due to the bonding. Moreover, it is still desired to provide a nonwoven elastic laminate material (e.g., a nonwoven elastic laminate web) that is cloth-like, stretchable and resilient, yet which retains good hand and drape properties after bonding. More particularly, it is desired to provide a stretchable cloth-like nonwoven laminate without the use of conventional laminate bonding methods, e.g., without mechanical needling, fusion, chemical bonding, etc.
It is further desired to provide a nonwoven material, either a single web or laminate, of elastic and/or nonelastic material, having the properties discussed above, by a simple method, using simple apparatus.
While the above-discussed documents may disclose products, processes and apparatus which exhibit some of the characteristics of the present invention, none of them discloses or suggests the present invention, including the advantages thereof, which achieve the objectives as discussed below.